Speed varying mechanism



Jan. 2, 1940. D, E. LEWELLEN ET AL SPEED VARYING MECHANISM 3Sheets-Sheet 1 Filed March 15, 1937 2 Pl 9. 2 ln.

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Patented Jan. 2, 1940 UNITED STATES PATENT OFFICE Darcy E. Lewcllen andEmmons F. Lcwellen,

Columbus, Ind.

Application March 15, 1937, Serial No. 130,843

Claims.

- anisms, and in particular, to such mechanisms which employ conepulleys with separable halves. One object of this invention is toprovide a 5 speed varying mechanism wherein the separate cones of avariable speed pulley are positively driven and positively positioned bymeans acting also to convey power to the pulley from the drive shaft.

Another object is to provide such a speed varying mechanism, wherein thepositive driving means consists of a link operatively connected to bothpulley halves and adapted to maintain a constant driving connectiontherewith, regardless of the position of the pulley halves.

Another object is to provide a variable speed mechanism, wherein a fixedpulley and a separable cone pulley are mounted on substantially parallelshafts, and interconnected by a belt, mechanism being provided forvarying the distance between the shafts, the separable cone pulleyhaving means therein for positively driving both pulley halvesregardless of their relative positions.

Another object is to provide a variable speed mechanism having resilientmeans for urging the pulley halves in opposite directions, andtelescoping means for forming a closure and retaining the lubricantwithin the device.

36 In the drawings:

Figure 1 is a central vertical section through the variable speed pulleyof this invention, showing the pulley halves in their closed or maximumdiameter positions.

Figure 2 is a view similar to Figure 1, but showing the pulley halves intheir open or minimum diameter positions.

Figure 3 is a vertical cross section along the line 3-3 in Figure 1.

Figure 4 is a vertical cross section along the irregular line 6-41 inFigure 1.

Figure 5 is a vertical longitudinal section of the hub of the left-handpulley cone in Figure 1, looking in the opposite direction.

4:, Figure 6 is a bottom plan view of the pulley hub shown in Figure 5.

Figure 7 is a central vertical section through the right-hand pulley hubof Figure 1, looking in the opposite direction.

50 Figure 8 is a bottom plan view of the hub of the pulley half shown inFigure 7.

Figure 9 is a top plan view of a speed varying mechanism according tothis invention.

Figure 10 is a perspective view of one of the 55 driving pins for thevariable speed pulley halves.

This invention relates to speed varying mech- In general, the speedvarying mechanism or device of this invention consists of a pair ofsubstantially parallel shafts with a pair of separable cones mounted onone shaft and movable axially therealong. These separable cones arepositively driven by a link connected to the motor drive shaft in such amanner as to provide a positive driving and positioning arrangement,regardless of the relative positions of the pulley halves. Anotherfeature of the invention is the provision of a telescoping casingsurrounding the spring which urges the pulley halves in oppositedirections.

Referring to the drawings in detail, Figure 9 shows a motor I0 mountedon a carriage II, which is movable relatively to a base I2 by means of ascrew shaft I3 operated by a hand wheel M. The motor I6 is provided witha motor shaft I5 having a driving shaft I6 secured thereto, as by thesocket Il, into which the motor shaft I5 is extended. A key I8 providesa driving connection between the motor shaft I5 and the drive shaft I6,and a set screw IS in a threaded hole 20 provides means for locking theassembly of the motor shaft l5 and drive shaft I6 together. The driveshaft I6 is provided at its right-hand or opposite end with a slot 2|(Figures 1 and 4), and a transverse threaded hole 22 containing athreaded pivot pin 23. The drive shaft I6 is also provided with aflattened portion 24 along the top right-hand end, as shown in Figures 1and 4.

Mounted upon the drive shaft I6 is a conical pulley half 25 having a hub26 extending longitudinally along the shaft I6. An oil space 21 isprovided therebetween and equipped with a lubricating connection 28 forproviding lubricant to the space 21 through the bore 29. The hub 26 isin the form of a sleeve, having cutaway portions 30 and 3| at the topand bottom, respectively (Figures 1, 5 and 6) and also is provided withan oil groove 32 communicating with the shaft I6 by means of the oilhole 33 (Figure 5). A hole 34 provides access to the pivot pin 23, and athreaded portion 35 serves for receiving a nut 36 for the purpose ofretaining the various parts mounted upon the hub 26.

The hub 26 of the pulley half 25 is provided in its upper portion withan internally extending shoulder 26a having a transverse slot 31therethrough (Figures 1 and 5) and this slot serves to receive atransverse driving pin 38 having fiattened ends 39 (Figure 10). Theflattened ends 39 engage the side walls of the slot 31, whereas thecentral portion passes through a bore 40 in a link havinga transversehole 42 for receiving the pivot pin 23 and forming a pivotal mountingthereof. The opposite end of the link 4| is provided with a transversehole 43, receiving the midportion of a driving pin 44 having flattenedends 45, similar to the flattened ends 39 of the driving pin 38. Theseflattened ends 45 engage the side walls near the opposite ends of atransverse slot 46 (Figures 1 and 7) in the sleeve-like hub 41 of asecond conical pulley half 48 mounted upon and slidable along the hub 26of the first pulley half 25. The hub 41 is provided near its outer endwith a cutaway portion 49 forming a chamber, permitting the motion ofthe upper end of the link 4| to and fro from the closed position ofFigure 1 to the open position of Figure 2. The hub 41 is likewiseprovided with longitudinal ribs 49a, these ribs giving a strengtheningeffect to the hub. The lower end of the link 4| similarly moves throughthe cutway portion 5| in the hub 41.

The hub 41 of the cone pulley half 48 is surrounded by a spiralcompression spring 58 (Figure 1), the inner end of which engages theflanged portion 52 of an outer telescoping member 53, which in turn,engages the annular wall 54 of the cone pulley half 48. The opposite endof the coil spring similarly engages the flanged portion 55 of the innertelescoping member 56, the latter in turn, engaging the flange 51 uponthe nut 36. Consequently, the telescoping portions 53 and 56 form aprotecting casing over the spring 50 and the slidable hubs 41 and 26,thereby reducing the escape of lubricant and preventing the entrance ofdust or other foreign matter which might interfere with the smoothworking of the various parts. A hole 58 in the hub 41 corresponds to thehole 34 in the hub 26..

The pulley halves 25 and 48 are engaged upon their conical innersurfaces 59 and 60 by a V- belt 6|, of any suitable form. This mayconsist, for example, of a rubber and fabric V-belt or else a beltformed of interconnected slats. The edges of the belt 6| also engage theinner conical walls 62 and 63 of a fixed diameter cone pulley 64 (Figure9), this having a hub 65 mounted upon a shaft 66. Alternatively theinner surface of the belt 6| may engage the surface of a flat-facedfixed pulley (not shown). In the latter case, friction pads 61 may beadded to the inner surface of the interconnected slat belt to provide afriction driving surface.

In the operation of the variable speed mechanism or transmission of thisinvention, the axes of the shafts I6 and 66 (Figure 9) are varied byturning the hand wheel l4 and the screw shaft 3, thereby causing thecarriage H and motor H) to move relatively to the base l2. If thedistance between the shafts 66 and 6 is increased, the belt 6| forcesthe pulley halves 48 and 25 apart, thereby approaching the positions ofFigure 2 at the extreme limit of motion. This occurs because the belt 6|has a constant length. When the pulley halves 25 and 48 are thusseparated, the spring 50 is compressed and the tubular members 53 and 56telescope relatively to each other (Figure 1). The edges of the belt 6|,therefore, engage the halves 25 and 48 upon a reduced diameter, andtherefore impart a slower speed to the shaft 66 because the pulley 64maintains a constant diameter.

, If, however, the hand wheel l4 and screw shaft |3 are moved in theopposite direction, so that the carriage H and shaft I6 move toward theshaft 66, the force of the spring 50 urges the pulley halves 25 and 48toward one another as the belt 66 slackens. The pulley halves 25 and 48eventually reach their extreme or closed positions, shown in Figure 1.Meanwhile, the rotation of the motor shaft |5 transmits power to thedrive shaft l6, which in turn, positively transmits power through thelink 4| to the inner and outer pulley hubs 26 and 41 by way of the slots30 and 5| therein.

It will be seen from a comparison of Figures 1 and 2, that the pivotedlink 4|, with its pins 38 and 44, maintains a positive driving andpositioning engagement with the pulley hubs 41 and 26 during theirentire motion between the extreme positions of Figures 1 and 2. In thismanner the pulley halves are enabled to maintain a fixed center line sothat the fixed pulley 64 does ,the pulley halves 25 and 48 and the driveshaft Hi. The telescoping tubular members 53 and 56 form a constant andtight closure over the spring 50 and the other parts of the variablespeed pulley shown in Figures 1 and 2.

It will be understood that we desire to comprehend within our inventionsuch modifications I as come within the scope of the claims and theinvention.

Having thus fully described our invention, what we claim as new anddesire to secure by Letters Patent, is:

1. In a variable speed device, a shaft, a pair of cone-faced discsmounted on said shaft, at least one of said discs being movable axiallythereon, a driving element pivotally mounted on said shaft on a pivotaxis passing through the vicinity of the axis of rotation of said shaft,one of said discs having a hub slidably mounted relatively to saidshaft, said hub having a slotted portion, and means near the end of saiddriving element for drivingly engaging said slotted portion.

2. In a variable speed device, a shaft, a pair of cone-faced discsmounted on said shaft, both of said discs being movable axiallytherealong, said discs having telescoping hubs mounted for motion alongsaid shaft, said hubs having portions with transverse slots therein, adriving element pivotally connected to said shaft on a pivot axispassing through the vicinity of the axis of rotation of said shaft, andcontact elements mounted on the opposite ends of said driving element inengagement with the slots in said hubs for drivingly engaging andpositioning said hubs relatively to said driving element.

3. In a variable speed device, a shaft, a pair of cone-faced discsmounted on said shaft, both of said discs being movable axiallytherealong, means for varying the diameter of engagement of said beltwith said discs, said discs having telescoping hubs mounted for motionalong said shaft, said hubs having cutaway portions, a driving elementpivotally connected to said shaft on a pivot axis passing through thevicinity of the axis of rotation of said shaft, and means operativelyinterconnecting the opposite ends of said driving element and said hubsand entering said cutaway portions of said hubs for drivingly engagingand positioning said hubs relatively to said driving element.

4. In a variable speed device, a shaft, a pair of pulley halves movablymounted on said shaft, a driving element connected to said shaft, saidpulley halves having telescoping hubs, connecting devices on saiddriving elerrient for drivingly engaging said hubs, a tubular casingconnected to one of said pulley halves, a second tubular casing intelescoping relationship therewith connected to the hub of the otherpulley half, and an elongated coil spring encircling said shaft withinsaid telescoping tubular casings and constructed and arranged to urgesaid pulley halves toward each other.

5. In a variable speed device, the combination of an expansible pulleyformed by two pulley halves having telescoping hubs and movable axiallyrelatively to form a belt pulley of varying diameter, a driving elementfor said pulley, connecting devices between said driving element andpulley, a tubular casing connected to one of said pulley halves, asecond tubular casing in telescoping relationship therewith connected tothe hub of'the other pulley half, and an elongated coil springencircling said hub within said telescoping tubular casings andconstructed and arranged to urge said pulley halves toward each other.

DARCY E. LEWELLEN.

EMMONS F. LEWELLEN.

